Gas burners



R. v. SHORT GAS BURNERS Filed Nov. a, 1957 Mmh 3, 1970v NwM INveNI-r-olgRONALD Vim-.m SHOW C3)/ v :2M #Mwah Amwlys United States Patent3,498,545 GAS BURNERS Ronald Victor Short, 105a Wickland Ave., Saltdean,

Brighton, Sussex, England Filed Nov. 8, 1967, Ser. No. 681,497 Claimspriority, application Great Britain, Nov. 9, 1966, 50,160/ 66; Feb. 22,1967, 8,403/ 67 Int. Cl. B05b 7/12 U.S. Cl. Z39-417.5 1 Claim ABSTRACT0F THE DISCLOSURE A single-stage gas burner so constructed as to be ableto burn natural gas which has a caloric value far higher than that oftowns gas or town gas and which is supplied at a far higher mainspressure. The design of the annular space into which air is entrainedcombined with the number of air ports (or the total area of the airports) through which the entrained air passes create correct aerationfor combustion and velocity such as to prevent lighting back.

This invention relates to gas burners.

The advent of so-called natural gas (which term is intended to includethe gas which is being found =by the companies or consortia which areoperating deep sea drilling rigs in the North Sea off the east coast ofEngland) makes it necessary to redesign existing gas burners or todesign new gas burners because of the high mains pressure at which thenatural gas will be supplied to the consumer and because the natural gashas a high calorific value.

Towns gas is, in general, supplied at a mains pressure of ve incheswater gauge which is stepped down to two and a half inches water gaugefor consumers use. Natural gas, on the other hand, will in allprobability be supplied at a mains pressure of the order of twentyinches water gauge which will be stepped down to, say, eight incheswater gauge for consumers use. Further, the calorific value of towns gasis of the order of 400 to 500 B.t.u. whereas that of natural gas is ofthe order of 1000 B.t.u. or more.

The principal object of the present invention is, therefore, to providea gas burner which will give the degree of aeration necessary to producea mixture of air and natural gas which will .burn satisfactorily at theburner head and will not light back.

It is known that a right circular cone is obtained by rotating aright-angled triangle using one of its legs or sides as the axis ofrotation. Any reference herein to an element or part of the gas burneras being frusto-conical refers to the frustum of a right circular conewhich is obtained by the base of the triangle forming a right angle withthat side of the triangle which is equal to the height of the triangleand -which is used as the axis of rotation, the hypotenuse of saidtriangle being inclined with respect to said base at an angle which will'hereinafter be referred to as the angle of the cone.

According to a first aspect, the present invention consists in asingle-stage gas burner which includes amain body defining a passageway,an injector and a burner head having burner ports therein; saidpassageway having a cylindrical first portion, a second portion which isfrustoconical and which has the end thereof which is of largest diameterconnected to said cylindrical first portion, and a third portion whichis frusto-conical and which has the end thereof which is of smallestdiameter connected to that end of said second portion which is ofsmallest diameter, said rst, second and third portions being axiallyaligned with one another; said injector including a body r* 3,498,545Ice Patented Mar. 3, 1970 of which at least a part is intended foraccommodation in said cylindrical first portion and a nipple which is offrusto-conical section and which is coaxially arranged with respect tosaid first and second portions and which has at least one axiallyextending injector orifice therein; the angle of the cone of saidfrusto-conical second portion falling within the range from 50 to 60 andthe angle of the cone of the frusto-conical nipple falling within therange from 40 to 50; and at least two radial air ports formed in thatpart of said main body which -deiines said cylindrical first portion ofsaid passageway.

Preferably, the angle of the cone of said second portion is 60 and theangle of the cone of said nipple is 50.

In one embodiment according to the invention, the annular passagedefined on the one hand 4by the exterior surface of the frusto-conicalnipple and on the other hand by that part of the inner surface of themain body which defines said second portion of said passageway is suchthat the ratio between the dimension of the radially outer end of saidannular passage and the dimension of the radially inner end of saidannular passage is of the order of one and one half.

In another embodiment according to the invention, the downstream end ofthe injector orifice is located axially of the tube, :between those endsof said second portion of said passageway which are of largest andsmallest diameters.

In another embodiment according to the invention, the diameter d of eachair port and the distance D between the throat formed by the junction ofthose ends of the second and third portions which are of the smallestdiameter on the one hand and the centre of the nipple (said centre beingsubstantially coincident with the longitudinal axis of said main body)on the other hand are such that the ratio D/d is equal to or is of theorder of 1.5.

In yet another embodiment according to the invention, the area a of thethroat formed by the junction of those ends of the second and thirdportions which are of the smallest diameter on the one hand and thetotal A of the areas of the individual air ports are such that the ratioA/a ranges from 11A: to 2.

The present invention will now be more particularly described withreference to the accompanying drawing in lwhich:

FIGURE l illustrates an axial section of the preferned embodiment of asingle stage gas burner according to the present invention; and

FIGURE 2 illustrates an axial section of an alterative embodiment lofsuch a burner.

Referring to FIGURE l, there is illustrated diagrammatically therein agas yburner having a main body 10 defining a passageway, an injector 11and a burner head 12 having burner or flame ports 13 therein. Thepassageway defined by the main body 10 comprises a cylindrical firstportion 14, a second portion 15 which is frusto-conical and a thirdportion 16 which is frusto-conical. It will be noted that the threeportions 14, 15 and 16 are axially aligned and are connected to oneanother so as to form a continuous passageway of which a part is theburner tube. Two radial air ports 17, 18, which are diametricallyopposed to one another, are provided in the main body 10, each portbeing (if circular) of a diameter such that said Iport extends axiallyof the body 10 from a point or region of said body 10 which is adjacentthat part of the frustoconical portion 15 which is of largest diameterto a point or region of said body 10 which is adjacent that part of afrusto-conical nipple 19 which is of largest diameter. The nipple 19 hasan axially directed orifice 20.

The preferred value of the angle A of the cone of the frusto-conicalportion 15 is 60 whereas the preferred value of the angle B of the coneof the frusto-conical nipple 19 is 50, and these two angles provide anannular passage which is in communication with the ports 17, 18 and alsowith the throat T (which is formed at the junction of the two connected-parts of the portions 15, 16 which are of smallest diameter) and withthe space in the immediate vicinity of the downstream end of the orifice20. The ratio between the dimension of the radially outer end of saidannular passage (which dimension is equal or substantially equal to theshortest distance between that part of the nipple 19 which is of largestdiameter and that part of the second portion 15 which is of largestdiameter) and the dimension of the radially inner end of said annularpassage (which dimension is equal or substantially equal to the shortestdistance between that part of the nipple 19 which is of smallestdiameter and the throat T) is of the order of one and one-half (1.5),said dimensions being calculated by reference to one half of any axialsection of said annular passage.

Said downtsream end of the orice 20 is located, axially of the burnertube (or axially of the portion of the gas burner in which air entrainedthrough the ports 17, 18 mixes with the gas stream emerging from theorifice 20), between the diametral planes containing those parts of theportion 15 which are of largest and smallest diameters.

The angle A of the cone of the frusto-conical portion 15 may be selectedfrom the range from 50 to 60 and, similarly, the angle B of thefrusto-conical nipple 19 may be selected from the range from 40 to 50.It is considered to be essential, however, that the angle A shouldalways be greater than the angle B by an amount which is of the order ofReferring now to FIGURE 2, there is illustrated therein a single stagegas burner (without the burner head thereof) in which the parts thereofwhich are the same as those of the burner shown in FIGURE 1 areindicated by the same reference numerals as have been employed in thedescription of said FIGURE 1. Thus, a main body 10 is provided withradial air ports 11 of which four are visible and of which the remainingtwo (of the total of six) are provided in the portion of said main bodywhich has been cut away. The main body 10 denes a passageway havingintermediate its ends a frusto-conical portion of which the end ofsmallest diameter forms a throat T, said passagewaybeing completed onthe one hand by a cylindrical portion 14 and on the other hand byanother frusto-conical portion 16, said portions 14,

15 and 16 ybeing connected to one another in the manner alreadyexplained with reference to FIGURE 1. There is also provided afrusto-conical nipple 19 having, as illustrated, one axially extendinginjector orifice 20, said nipple being constructed as already describedwith reference to FIGURE l.

`If the ratio D/d is increased, (in other words, if D is increasedwithout increase of d), aeration is increased beyond the desirable limitand the ame is inclined to lift from the burner ports, D being thedistance between the throat (formed by the junction of the portions 15,16) and the centre of the nipple 19, and d being the diameter of eachair port 11.

Further, and `by way of example, with a 1% gas injector in which thediameter of the throat T is 3A inch and each air port of the six airports 11 has a diameter of 3A; inch, the ratio A/a is approximately11/2, A being the sum of the areas of the individual ports 11 and abeing the area of the throat T.

By way of a further example, with a '1/2' gas injector in which the areaa of the throat T is 0.11 square inch and the sum A of the areas of thesix individual air ports 11 is 0.2256 square inch, the ratio A/a isapproximately 2.

What I claim as my invention and desire to secure by Letters Patent ofthe United States is:

1. A single-stage gas burner which includes a main body defining apassageway, an injector and a burner head having burner ports therein;asid passageway having a cylindrical first portion, a second portionwhich is frusto-conical and which has the end thereof which is oflargest diameter connected to said cylindrical first portion at one endthereof, and a third portion which is frusto-conical and which has theend thereof which is of smallest diameter connected to that end of saidsecond portion which is of smallest diameter, said connection forming athroat of predetermined diameter, the larger end of said third portionhaving a restricted portion leading to the burner head, said rst, secondand third portions being axially ailgned with one another, orices insaid cylindrical portion closely adjacent its connection with saidfrusto-conical portion, said injector including a nipple having afrusto-conical end portion slidably and sealably received in the otherend of said cylindrical portion, said frusto-conical end portion havingan orice coaxially arranged with respect to said throat and adjacentsaid orifices, said orifices being the sole air inlet openings, and theangle of the cone of said second portion being substantially and theangle of the cone of the nipple being substantially 50 whereby theannular passage formed therebetween ares inwardly.

References Cited UNITED STATES PATENTS 623,043 4/1899 Shaffer 239-430945,899 1/ 1910 Achee Z39-434.5 1,049,848 1/1913 Goreau Z39-434.52,008,130 7/1935 Damm Z39-434.5

FOREIGN PATENTS 393,925 11/1908 France.

EVERETT W. KIRBY, Primary Examiner U.S. Cl. X.R. 239-428, 430, 43 4.5

